Foam core sandwich splint

ABSTRACT

A multi-layered composite material suitable for use in orthopedics includes a foam core layer bonded between two layers of thermoformable polymer material. The thermoformable material is heat formable within a target temperature range allowing for rapid heating and application to a patient such as in the form of a splint. While within the target temperature range, the composite material includes a dwell time sufficiently long to enable proper fitment and adjustment, yet not overly long requiring extended periods of holding the composite material in place. The composite material is very light yet extremely rigid and easily conformable to patients.

INCORPORATION BY REFERENCE TO RELATED APPLICATIONS

Any and all priority claims identified in the Application Data Sheet, orany correction thereto, are hereby incorporated by reference under 37CFR 1.57. This application is a continuation of U.S. application Ser.No. 15/082,690, filed Mar. 28, 2016, now U.S. Pat. No. ______, which isa continuation of U.S. application Ser. No. 13/836,660, filed Mar. 15,2013, now U.S. Pat. No. 9,295,748, which claims the benefit of U.S.Provisional Application No. 61/677,779, filed Jul. 31, 2012. Each of theaforementioned applications is incorporated by reference herein in itsentirety, and each is hereby expressly made a part of thisspecification.

FIELD OF THE INVENTION

The present invention related generally to orthopedic braces. Morespecifically, the present invention relates to a thermoformable splinthaving a composite material construction.

BACKGROUND OF THE INVENTION

Orthopedic splints are typically used during the first few days of aserious injury such as a fracture, ligament tear or other injury thatneeds to be stabilized while swelling subsides. Splints are typicallypartially circumferential or they may wrap around an elbow or ankle andextend up both sides allowing a space on either side. They allow forswelling to occur and are typically wrapped with an Ace-type bandage orthe like, which is elastic and may provide compression, yet stretches toaccommodate swelling. A complication, Compartment Syndrome, may occur ifan injury is casted too soon or splinted too tightly which causes tissueto rapidly die from pressure buildup. Temporary proper splintingmitigates most complications in this regard. Typically, after 4-10 days,the splint is removed for procedures to reduce fractures, surgery or thelike.

Conventional splints may be constructed from uncured plaster-impregnatedfabric, or fiberglass impregnated with resin that is water activated.They are initially pliable and soaked in water to activate the curingprocess. Such conventional splints typically come in rolls or pre sizedblanks.

While conventional splints are sufficient for their intended purpose,they do exhibit a number of drawbacks which can be improved upon. Forexample, some sort of padding must be applied to the limb prior toapplying the splint. The splint material must be soaked in water tobegin the curing process, and variables such as water temperature androom humidity can alter the cure time for the splint material. Oncewetted, the splint material is applied over the padding, which must bekept in proper alignment to be effective. Prior to wetting, the splintmaterial is trimmed to a rough desired shape, but upon wetting andapplication to a patient, additional trimming of the material is oftenneeded. The process is quite messy, and must be carried out very quicklybefore the splint material begins to cure. Initial curing can start in2-5 minutes depending on the product and water temperature used. Onceinitiated, there is no stopping it and the application process must becompleted with precise timing to allow for the body part to be aligned,reduced in fracture or otherwise completed before the splint cures. Thisprocess requires considerable training and the practitioner must havethe splint in place in time to make the final alignment while the splintis still soft enough. Often, there is a minor complication or the splintis wetted too early or too warm and the curing starts during applicationso there is not enough time to finish the job properly before curing. Inthis case, the splint must be discarded and the process started over.This not uncommon occurrence is very wasteful, time consuming andcostly, not to mention uncomfortable for the injured patient. Wrappingthe padding and splint material can often take two people to support andwrap, and the manipulation is often painful to the patient.

On occasion, for a complicated reduction or alignment of a fracture orother injury, an X-Ray or fluoroscope view is needed during theprocedure to see through the body to accomplish the correct procedure.Fiberglass and plaster materials tend to scatter X-rays and are somewhatimpenetrable, so the view is typically obscured. These poor images canpose problems and the images must often be made with the patient at oddangles so as to image through the body without imaging through much ofthe splint. This can require complicated alignment of the machinery andpatient which can cause great discomfort and complication.

Additionally, complicated reduction and alignment procedures may requirea short period of sedation of the patient as the pain is too great toendure. The patient could react and possibly spoil the procedure. All ofthis can require a number of qualified people in close proximity doingseveral procedures at once. Along with the usual practitioners, thegroup can grow quite large. Everything must be orchestrated preciselyand timed with the curing of the splint.

Another concern with conventional splinting materials and techniques isthe wet environment created during their use. Because plaster andfiberglass splints will typically remain damp for 12 hours or more asthe moisture slowly dissipates from the splint and padding through theAce-type wrap, the moist environment from the splint combined with thebody's heat and moisture provides the ideal place for bacterialreproduction.

This wet insulated environment also can provide a great deal ofdiscomfort to the patient, especially in warm climates. Additionally,both fiberglass and plaster are virtually sealed against moisturepassing through them so the splints do not breath or allow moisture toeasily escape from inside near the body. Any moisture management must beprovided by the thick padding or other wrapping.

In view of the drawbacks of conventional splints, a need exists for animproved splint which is less messy, requires fewer personnel to apply,has less likelihood of wasted material due to improper application, andis more comfortable and hygienic for the patient.

One proposed improvement on conventional splints is described incommonly assigned U.S. Published Patent Application No. 2012/0101417 toJoseph, which describes a splint having a composite laminateconstruction, consisting of thermoformable middle layer, and outerlayers of foam and/or fabric which represents an improvement onconventional splints. Opportunities for improvement on the splintsdescribed therein still exist, however.

Additionally, prior splint constructions utilizing one or more polymerlayers for rigidity typically include either a thin layer of polymersheet material which is prone to flexing and twisting, or a thickerlayer which can provide sufficient rigidity but is unable to be formedinto complex shapes or contours and is unacceptably heavy.

A need exists, therefore, for an improved construction for splints whichis lightweight, formable to the contours of a patient's anatomy, andwhich is sufficiently rigid to support the injury.

SUMMARY OF THE INVENTION

In one embodiment, the present invention comprises a composite materialincluding a first layer of thermoformable material, a second layer ofthermoformable material, and a foam layer disposed between, and bondedto, the first and second layers of thermoformable material, wherein thefirst and second layers of thermoformable material are heat formablewithin a target temperature range and substantially rigid attemperatures below a minimum formable temperature of about 130 degreesFahrenheit.

In another embodiment, the present invention comprises a methodincluding causing a composite material to be manufactured and madeavailable to a user, and providing instructions to the user for creatinga splint with the composite material. The composite material comprises afirst layer of thermoformable material, a second layer of thermoformablematerial, and a foam layer disposed between, and bonded to, the firstand second layers of thermoformable material, wherein the first andsecond layers of thermoformable material are heat formable within atarget temperature range and substantially rigid at temperatures below aminimum formable temperature of about 130 degrees Fahrenheit. Theinstructions for creating a splint with the composite material includeheating the composite material such that the layers of thermoformablematerial are above the minimum formable temperature, forming thecomposite material about a body part while the layers of thermoformablematerial are above the minimum formable temperature, and holding thecomposite material in place until expiration of the dwell time such thatthe layers of thermoformable material are below the minimum formabletemperature.

In another embodiment, the present invention comprises a method ofapplying a splint to a patient, comprising providing a compositematerial including a first layer of thermoformable material, a secondlayer of thermoformable material, and a foam layer disposed between, andbonded to, the first and second layers of thermoformable material,wherein the first and second layers of thermoformable material are heatformable within a target temperature range and substantially rigid attemperatures below a minimum formable temperature of about 130 degreesFahrenheit. The method further comprises heating the composite materialsuch that the layers of thermoformable material are above the minimumformable temperature, forming the composite material about a body partwhile the layers of thermoformable material are above the minimumformable temperature, and holding the composite material in place untilexpiration of the dwell time such that the layers of thermoformablematerial are below the minimum formable temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention may be more completely understoodin consideration of the following detailed description of variousembodiments of the invention in connection with the accompanyingdrawings, in which:

FIG. 1 is a schematic cross-section of the composite material accordingto an embodiment of the present invention.

FIG. 2 is a table depicting suitable material properties of athermoformable material layer of the composite material according to anembodiment of the present invention.

FIG. 3 is a table depicting suitable material properties of a foam layerof the composite material according to an embodiment of the presentinvention.

While the various embodiments of the invention are amenable to variousmodifications and alternative forms, specifics thereof have been shownby way of example in the drawings and will be described in detail. Itshould be understood, however, that the intention is not to limit theinvention to the particular embodiments described. On the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the inventions as may be claimed.

DETAILED DESCRIPTION OF THE DRAWINGS

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinventions as claimed.

Although embodiments of the present invention are described chiefly incontext of a splint, it should be appreciated that the materials,construction techniques, and methods described herein are alsoapplicable to other orthopedic products such as braces, or for use assupports in combination with other orthopedic products.

The splints described in U.S. Pat. No. 8,303,527 to Joseph and U.S.Published Patent Application No. 2012/0101417 to Joseph, the disclosuresof which are incorporated herein by reference, present a significantimprovement over conventional wet lay-up splints but room for furtherimprovement still exists. For example, certain splinting situations maycall for a more rigid structure than is possible with the materials andstructures described in these publications.

Referring now to FIG. 1, embodiments of the present invention generallycomprise a composite sandwich material 20, having two layers ofthermoformable material 22, 24, separated by a foam core layer 26, andoptionally one or more finishing layers 28, 30.

The thermoformable material 22, 24 may include material properties asdepicted in FIG. 2. Thermoformable material 22, 24 is preferably rigidat room temperatures, and more preferably rigid at temperatures belowabout 130 degrees Fahrenheit. Thermoformable material 22, 24 may be heatformable within a target temperature range of about 160-240 degreesFahrenheit, and more suitably within a range of 190-225 degreesFahrenheit. The minimum heat formable temperature may be about 160degrees Fahrenheit, or about 150 degrees Fahrenheit, or about 140degrees Fahrenheit. Advantageously, the target temperature range isrelatively low, allowing quicker heating times, while the minimum heatformable temperature is high enough to prevent unintended alterations ofshape during normal use if accidentally exposed to high temperatures.

Within the target temperature range, thermoformable material 22, 24 ispliable and shapeable to the profile of a patient. Thermoformablematerial 22, 24 may include a dwell time of about three minutes to tenminutes, or of about five minutes to ten minutes. Dwell time refers tothe amount of time that thermoformable material 22, 24, once heated towithin its target temperature range, is at least partially shapeable. Inone embodiment, after being heated to within the target temperaturerange, thermoformable material 22, 24 is at least partially rigid afterfive minutes such that during a fitting process, a healthcareprofessional may cease applying pressure to the splint after fiveminutes and allow thermoformable material 22, 24 to fully cure withoutfurther intervention for the remainder of the dwell time. As utilized incomposite material 20, a suitable thickness range of thermoformablelayers 22, 24 is from about 0.030 inch to about 0.075 inch for eachlayer, with a more suitable range from about 0.035 inch to about 0.045inch for each layer. In another embodiment, the thermoformable materialmay include glass strand added to the polymer to further increasemodulus.

Foam layer 26 preferably comprises a closed cell foam, and is of arelatively high density. Suitable materials for construction of foamlayer 26 in whole or in part may include low density polyethylene(LDPE), medium density polyethylene (MDPE), high density polyethylene(HDPE), polyethylene terephtalate glycol-modified (PETG), polyolefinblends, optionally any of these blended with ethylene-vinyl acetate(EVA), and any of which may or may not be crosslinked. One preferreddensity of foam layer 26 is from about 150 to 300 kg/m̂2 or about 16 to20 lbs/sq. ft. Suitable thickness of foam layer 26 is from about 1 mm toabout 3 mm, with a more suitable range from about 1.5 mm to about 2 mm.In one embodiment, the thickness of foam layer 26 is about double thethickness of one layer of thermoformable material 22, 24. In oneembodiment, the foam layer has properties as listed in FIG. 3, and isavailable under the name Microzote which is a LDPE fine celled closedcell foam blown with an inert gas and lacking reactive agents as arecommonly used. Foam layer 26 thus provides a connective layer betweenthermoformable layers 22, 24 that is somewhat compliant and formablewhen heated, yet rigid and connected enough to resist compression andshearing thus allowing multi-layered composite material 20 to act as aunitized structure.

The combination of two layers of thermoformable material 22, 24 and foamcore 26 results in a very light, thin, and rigid piece of compositematerial 20 which is extremely rigid when formed into a threedimensional shape.

Finishing layers 28, 30 may be selected from a variety of materials.Typically, one of layers 28, 30 will be positioned against the skin ofthe patient thereby comprising an inner layer, and therefore suitablematerials will be comfortable, breathable, antimicrobial, and/or padded,and may comprise closed cell foam, open cell foam, an insulating fabric,a multilayer or lofted insulating fabric layer, or any other suitablematerial. While open cell foam is desirable for breathability, a closedcell may be advantageous for waterproof characteristics. Optionally, anadditional layer may be included which is configured to be in contactwith the skin of the patient, the additional layer comprising a fabricthat is comfortable on the skin and wicks moisture into the layer 28, 30for dissipation.

The other of layers 28, 30 will typically comprise an outer layer, andsuitable materials will be durable, such as knit nylon spandex blend,knit polyester spandex blend, nylon fabrics, polyester or other fibersthat stretch due to the design of the knit, rubberized materials, orfoams such as urethane foam, foam rubber or EVA foam. Additionally,unbroken loop fabric, which is operably coupleable to hook-typefasteners, may be included as part of one of layers 28, 30 so as toprovide functionality for hook-and-loop (VELCRO) type fasteningarrangements.

Referring now to construction of an embodiment of composite material 20,the multiple layers may be bonded together by means of hot melt, PSAadhesive, or even by heat and pressure alone. In one embodiment, layers22, 24, 26, 28 and 30 are laminated together at a temperature of 250-300degrees Fahrenheit, under pressure. Variations on the construction ofcomposite material 20 described herein may be made in order to alter thecharacteristics of composite material 20. For example, the thickness ofthe layers of thermoformable material 22, 24 may be varied such thateach layer has a unique thickness. The hardness of foam layer 26 may beincreased, to increase rigidity. The thickness of foam layer 26 may bevaried to vary the dwell time of thermoformable layers 22, 24.

Additional layers of material may also be added as desired, such asspacer fabric, reinforcing material, waterproofing material, and/oradditional foam layers for padding. The outer, middle and inner layersmay be joined at their edges, such as by sewing, gluing, thermal orchemical bonding, or other suitable methods. Composite material 20 maybe perforated with ventilation holes to aid in evaporation and coolingso transport occurs along foam layer 26 and out the vents.

In one embodiment, composite material 20 is provided for splinting,which can be fitted to a patient as follows. Composite material 20 isheated, preferably with a dry heat source such as an oven, microwave,heat gun, radiant lamp heat sources, infrared heaters, a heating bag,pouch, or other heat enclosure, or an exothermic heat source. Wet heatmay also be utilized by immersing composite material 20 into a containerof hot liquid such as water, or by placing composite material 20 withina liquid-filled bag and placing the bag in a microwave. Compositematerial 20 is heated for a length of time sufficient to bring thetemperature of the layers of thermoformable material 22, 24 within theirtarget temperature range such that composite material is pliable andformable to the patient. In one embodiment, composite material 20 isconstructed such that the layers of thermoformable material 22, 24 arewithin their target temperature range after ten minutes of heating. Inanother embodiment, composite material 20 is constructed such that thelayers of thermoformable material 22, 24 are within their targettemperature range after about five minutes of heating.

Once thermoformable material 22, 24 is within its target temperaturerange, composite material 20 is removed from the heat source and appliedto the desired location on the patient. While working in the dwell timeof the material, the material is shapeable as desired to the patient,yet will somewhat hold its shape. During heating of the compositematerial, the thin layers of thermoformable material tend to warmcomparatively faster than the foam and fabric layers, reducing theamount of time necessary to heat composite material 20 to its targettemperature. Foam layer 26, having a lower density than thethermoformable layers 22, 24, does not retain as much heat as thethermoformable layers 22, 24 so heat dissipates more quickly fromthermoformable layers 22, 24 and composite material 20 hardens morerapidly.

An outer bandage wrap may be utilized to retain the material in adesired shape, and/or the physician may hold the material in place withhis/her hands while the material cools. In another embodiment, auniversal closure system may be provided, such as those described inU.S. Pat. No. 8,303,527 to Joseph and U.S. Published Patent ApplicationNo. 2012/0101417 to Joseph. A suitable closure system includes aplurality of attachment members configured to releasably couple tocomposite material 20 such as by hook-and-loop fasteners, an elongatedflexible member configured to be routed through one or more guideelements affixed to the attachment members, and a tensioning mechanismconfigured to be operable so as to engage the flexible member andtighten the fit of composite material 20.

In another embodiment, the present invention comprises a kit includingcomposite material 20 according to one or more of the embodimentsdescribed herein, and a set of instructions recorded on a tangiblemedium for fitting composite material 20 to a patient as a splintaccording to the methods described herein. In one embodiment, theinstructions may comprise instructions for use (IFU) or directions foruse, according to the requirements of one or more regulatory bodiesand/or government agencies. The instructions may be intended for apatient, or for a health care professional. Alternatively, the kit mayinclude indications which link a user to electronically accessibleinstructions.

The composite material 20 described herein may be used in conjunctionwith other orthopedic products, such as those described in U.S. Pat. No.8,303,527 to Joseph, U.S. Published Patent Application No. 2012/0101417to Joseph, and application Ser. No. 13/674,613 to Joseph et al., thedisclosures of which are incorporated by reference herein. Compositematerial 20 may be utilized in place of previously-disclosed rigidsupports, or may be used selectively as a supplemental support such asto provide additional support and rigidity in select locations on anorthopedic product.

Various modifications to the embodiments of the inventions may beapparent to one of skill in the art upon reading this disclosure. Forexample, persons of ordinary skill in the relevant art will recognizethat the various features described for the different embodiments of theinventions can be suitably combined, un-combined, and re-combined withother features, alone, or in different combinations, within the spiritof the invention. Likewise, the various features described above shouldall be regarded as example embodiments, rather than limitations to thescope or spirit of the inventions. Therefore, the above is notcontemplated to limit the scope of the present inventions.

Persons of ordinary skill in the relevant arts will recognize that theinventions may comprise fewer features than illustrated in anyindividual embodiment described above. The embodiments described hereinare not meant to be an exhaustive presentation of the ways in which thevarious features of the inventions may be combined. Accordingly, theembodiments are not mutually exclusive combinations of features; rather,the inventions may comprise a combination of different individualfeatures selected from different individual embodiments, as understoodby persons of ordinary skill in the art.

Any incorporation by reference of documents above is limited such thatno subject matter is incorporated that is contrary to the explicitdisclosure herein. Any incorporation by reference of documents above isfurther limited such that no claims included in the documents areincorporated by reference herein. Any incorporation by reference ofdocuments above is yet further limited such that any definitionsprovided in the documents are not incorporated by reference hereinunless expressly included herein.

For purposes of interpreting the claims for the embodiments of thepresent inventions, it is expressly intended that the provisions ofSection 112, sixth paragraph of 35 U.S.C. are not to be invoked unlessthe specific terms “means for” or “step for” are recited in a claim.

What is claimed is:
 1. A composite material, comprising: a first layerof thermoformable material having a thickness of about 0.03 to 0.075inches, the first thermoformable layer being heat formable such that itis at least partially shapeable once heated to within a targettemperature range. a second layer of thermoformable material of about0.03 to 0.075 inches, the second thermoformable layer being heatformable such that it is at least partially shapeable once heated towithin a target temperature range; and a foam layer disposed between thefirst layer of thermoformable material and the second layer ofthermoformable material, the foam layer bonded to the firstthermoformable layer and second layers of thermoformable material. 2.The composite material of claim 1, wherein the target temperature rangeis about 160-240 degrees Fahrenheit.
 3. The composite material of claim1, wherein the minimum heat formable temperature is about 150 degreesFahrenheit.
 4. The composite material of claim 1, wherein the minimumheat formable temperature is about 140 degrees Fahrenheit.
 5. Thecomposite material of claim 1, wherein the first and second layers ofthermoformable material have a dwell time of about three to ten minutes,the dwell time being an amount of time during which the first and secondlayers of thermoformable.
 6. The composite material of claim 1, andwherein the foam layer has a thickness of about 0.04 to 0.12 inches. 7.The composite material of claim 1, wherein the target temperature rangeis about 190-225 degrees Fahrenheit.
 8. The composite material of claim1, wherein the first and second layers of thermoformable material have adensity which is about three to five times greater than a density of thefoam layer.
 9. The composite material of claim 1, wherein the density ofthe first and second layers of thermoformable material is about 1200kg/m³ and the density of the foam layer is about 300 kg/m³.
 10. Thecomposite material of claim 1, wherein the first thermoformablecomprises glass strand.
 11. The composite material of claim 1, whereinthe foam layer is about double the thickness of one of the first andsecond thermoformable layers.
 12. The composite material of claim 1,further comprising a first finishing layer disposed adjacent to thefirst thermoformable layer opposite the foam layer such that the firstthermoformable layer is between the first finishing layer and the foamlayer.
 13. The composite material of claim 12, further comprising asecond finishing layer disposed adjacent to the second thermoformablelayer opposite the foam layer such that the second thermoformable layeris between the second finishing layer and the foam layer.
 14. Thecomposite material of claim 1, wherein the first thermoformable layer,the foam layer, and the second thermoformable layer are laminatedtogether.
 15. The composite material of claim 1, wherein the thicknessof the first thermoformable layer is different than the thickness of thesecond thermoformable layer.
 16. The composite material of claim 1,wherein the foam layer has a lower heat density that the first andsecond thermoformable layers.
 17. A composite material, comprising: afirst layer of thermoformable material having a thickness of about 0.03to 0.075 inches, the first thermoformable layer being heat formable suchthat it is at least partially shapeable once heated to within a targettemperature range. a second layer of thermoformable material being heatformable such that it is at least partially shapeable once heated towithin a target temperature range; and a foam layer disposed between thefirst layer of thermoformable material and the second layer ofthermoformable material, the foam layer having a lower density that thefirst thermoformable layer and a lower density that the secondthermoformable layer.
 18. The composite material of claim 17, whereinthe target temperature range is about 160-240 degrees Fahrenheit, andwherein the first and second layers of thermoformable material have adwell time of about three to ten minutes, the dwell time being an amountof time during which the first and second layers of thermoformable. 19.The composite material of claim 17, and wherein the foam layer has athickness of about 0.04 to 0.12 inches.
 20. The composite material ofclaim 18, wherein the first and second layers of thermoformable materialhave a density which is about three to five times greater than a densityof the foam layer.